1. Field of the Invention
The present invention is related to a multi-point laser trapping device and the method thereof in which laser light is irradiated on a medium which includes micro-particles, and multiple micro-particles within said medium are simultaneously captured and arranged.
2. Description of the Related Art
In recent years, there have been proposals for technology related to laser trapping in which laser light is irradiated on micro-particles on the micrometer order which are included in a medium, and the particles are manipulated without contract by the momentum received and transferred by refracting that light acting on the micro-particles, and capturing the micro-particles; and this is applied to manipulating and processing macromolecular substances on the molecular level, and to bio-engineering type cellular manipulations, etc.
Now then, initially, single micro-particles within the medium were captured by the laser light, but recently, there have also been proposals for technology relating to multi-point laser trapping in which interference patterns of the laser light are formed on the medium using a Mach-Zehnder interferometer, a Fabris Perot interferometer, or a Michaelson interferometer, etc. and multiple micro-particles within the medium are simultaneously captured.
FIG. 3 is a conventional multi-point laser trapping device which utilizes a Mach-Zehnder interferometer as the interference pattern format on means, and Mach-Zehnder interferometer 23 is formed an the light route of the laser light which is irradiated from Argon laser 21 onto preparation 22. Mach-Zehnder interferometer 23 uses half mirror 24 to split the laser light in two, and after these respective light beams are reflected by mirrors 25 and 26, both are irradiated on half mirror 27, and interference patterns are formed on lens 28 by the interference of the two light beams based on the fact that both mirrors are slightly tilted, and this interference pattern is projected on preparation 22 through half mirror 29 and lens 30.
Moreover, preparation 22 is formed by packing medium 34 which includes micro-particles 33,33 in between slide glass 31 and cover glass 32, and multiple micro-particles 33 are simultaneously captured and arranged along the is interference patterns formed by Mach-Zehnder interferometer 23.
In addition, 35 is a CCD camera which monitors the behavior of micro-particles 33 within medium 34.
Nonetheless, if interferometer 23 is utilized in this way, because the light intensity is attenuated from the use of two half mirrors 24,27 and two mirrors 25,26 at a minimum, a high output laser such as an Argon laser, YAG laser, or He--Ne laser, etc. must be used, and this involves the problems of a large scale device, and high costs.
Moreover, because the coherence length of an Argon laser, which has a narrow spectrum width, is about 50 mm, it is possible to form interferometer 23 by splitting the light with half mirror 24. However, there is a problem with small scale, inexpensive lasers such as laser diodes which have a wide spectrum width in that it is extremely difficult to actually form the interferometer because the coherence length is just a few mm. Moreover, mirrors 24,25,26 and 27 which are utilized in the optical system of Mach-Zehnder interferometer 23 are easily affected by displacement caused by minute vibrations.